Dual-Resonant Step-Up AC/DC Converter Based on Fixed Frequency Pulse Overlapping Modulation

To overcome the limitation of voltage regulation in resonant switched capacitor topology and introduce the soft switching characteristics into AC/DC converter, a dual-resonant step-up AC/DC converter based on fixed frequency pulse overlapping modulation is presented in this paper. The voltage regulation is achieved by regulating the overlapping time of the two switching pulses, and the switching frequency can be fixed for simplifying the implementation. The operational principle, voltage gain, power factor correction performance and device stress are analyzed in detail. Moreover, a prototype with 85−135 V_rms input and 200 V/250 W output are built to verify the proposed modulation strategy, the peak power factor (PF) and the lowest total harmonic distortion (THD) can reach 0.998 and 7.08% relatively, and the peak power conversion efficiency can reach 93.52%.